The OL is a major problem, but overall lack of talent is as well. With the exception of a healthy Gronkowski, the Patriots skill position players consist of a bunch of guys that would get a ho-hum response in free agency. Edelman may be changing that this year, but he wasn't that highly coveted last offseason. I believe if you asked NFL defenses about the talent level of the Pats' skill guys, the responses would be consistently unimpressed. Nobody is up late worrying about how to slow down Amendola, Thompkins, Dobson, Hoo-Man, etc.